The invention relates to vehicles capable of traveling across various types of surfaces. More specifically, it is directed to a multi-terrain amphibious vehicle that may efficiently propel itself across bodies of water and effectively traverse both even and uneven terrain without substantial loss of traction. The vehicle is capable of crossing from one type of surface to another without undue interruption during the transition.
In many applications of surface vehicles, both military and non-military, the vehicle is likely to encounter widely varied types of surfaces in transporting its payload. It may not only encounter both water and land surfaces, it may encounter land surfaces of greatly varied terrain and surface characteristics. In most cases, time and other resource constraints do not permit avoidance measures by which the vehicle may circumvent or otherwise avoid operation on surfaces for which the vehicle is not particularly suited. Consequently, the unexpected characteristics of the surface to be traversed often make for insurmountable obstacles which delay, if not all together halt, the vehicle's mission. Even where the vehicle is capable of traversing different types of surfaces encountered, efficient traversal may not be possible because significant reconfiguration of one or more parts of the vehicle would be necessary if it is to continue its travel across a surface of significantly different attributes.
Accordingly, there is a need for a versatile vehicle which is equally adept at traveling not only through water and on land surfaces, but also land surfaces of widely varied attributes such as unevenness, hardness, and salinity. There is also a need for a vehicle capable of overcoming abrupt transitions and surface characteristics without the accompanying need to incur undue interruptions in the vehicles operation.
Amphibious vehicles capable of traveling across both water and land surfaces are known in the prior art. The Hensley U.S. Pat. No. 1,100,238 discloses a combination automobile/boat vehicle. It has propeller wheels capable of travel over land as well as water. The wheels are mounted on shafts each having a sprocket gear driven by a gasoline engine. The Nelson U.S. Pat. No. 3,418,960 relates to vehicle wheels that are particularly adapted for amphibious vehicles when traveling on ground such as water saturated soil, sand or shingle, in which normal wheels tend to spin and sink and for the propulsion of such vehicles when on a body of water. At least ten different forms of wheels that could be used are illustrated in the various figures and they are described in the specification. All of these wheels have a basic circular outer radial surface and they rotate about a central axis.
The Headrick U.S. Pat. No. 3,628,493 discloses impeller wheels for amphibious vehicles. The Wakayama et al U.S. Pat. No. 4,575,354 discloses a toy car having detachable non-circular wheels attached to an axle driven by a spring motor.
The Siren U.S. Pat. No. 4,878,451 is directed to an amphibian vehicle having a plurality of wheels mounted on each side. Two drive trains are provided for separately driving the wheels on the respective sides of the hull. The drive trains can be driven at differential speeds to steer the vehicle.
The Legoy et al U.S. Pat. No. 5,013,269 is directed to a modular navigation vessel equipped with rotating floats.
The Harvey U.S. Pat. No. 5,881,831 is directed to a multi-terrain amphibious vehicle having a plurality of non-circular propulsion members rotatably coupled to a chassis assembly for propelling the vehicle across a given surface. That vehicle includes a control mechanism for controlling the rotational velocities and phases of the respective propulsion members such that the propulsion members are cooperatively rotated to collectively impart a predetermined speed and direction of travel to the vehicle.